The technical field and the main application of the invention relate to the fabrication and the use of devices in emergency situations to block or seal, from the inside, accidental leaks in the hull or the deck of a boat which is on the water, although such a device may equally be used to block or seal an accidental hole in a tank such as a fuel tank, and in this case from the outside of that tank.
It is in fact known that a leak in a boat hull is a problem that can lead to its loss, even when sailing near the coast, and that often necessitates, over and above the intervention of the crew, to the help of exterior rescue means: thus this is the third cause of interventions by the crews of the French rescue service Société Nationale des Sauveteurs en Mer (SNSM). In 2002 the leaks of all types, including hull breaches, were the second cause of intervention by the United States Coast Guard, with 500 incidents causing 111 fatalities and more than 11 million dollars of material damages.
Although not obligatory since the updating of the French regulations (in division 240), the presence onboard pleasure vessels of a system for blocking or sealing leaks in an emergency is still widely recommended. The equipment available at present is limited to narrow breaches, however, and to the closing of through-hull fittings, thus of circular section.
There are in fact known various products developed and marketed for blocking or sealing leaks, such as wood plugs suited only to circular holes of small diameter: in practice their use is therefore limited to blocking or sealing through-hull fittings and valves.
There have also been developed flexible plugs such as those described in U.S. Pat. No. 8,689,717 (Artelier Studio), marketed under the trade mark “Truplug®”, and which are used in the same way as wooden plugs: they are described as being equally useful for larger, irregular and long breaches, but then use either a plug cut lengthwise or a plurality of these plugs, but then necessitate combining them with pumps because they cannot make a good seal; moreover tests on the water have cast doubt on their effectiveness.
Also known are systems that are inserted into the breach that has opened up in the hull and part of which is deployed externally like an umbrella; there may be cited in this field:
U.S. Pat. No. 5,253,602 (John B. Moriarty), which teaches a system comprising a rigid threaded shaft sheathed with a circular sleeve over which slides a collar articulated with ribs disposed like the spokes of a wheel, supporting an impermeable membrane; inserted through the breach, the system is opened like an umbrella and then pulled to block or seal the hole on the outside of the hull by pressing the membrane against the latter; the seal that is produced in this way can be improved by screwing a rigid cover onto the interior part of the rod after removing the handle and an annular air chamber may also be disposed between this cover and the umbrella, around the threaded rod and inflated to fill the gap with it.
Patent application WO88/08389 (Barelier) describing a “self-sealing functional plug device”, consisting of three elements that are threaded through the hole that it is required to block or seal and part of which is deployed on the outside like an umbrella to provide pressure resistance and a seal, but as in the previous patent a system of this kind is of a mechanical complexity that makes it difficult to use.
There may also be cited U.S. Pat. No. 5,305,702 (Donald E. Philips), which teaches a rigid central shaft inserted through the breach and attached to the outside of the hull by articulated lugs, the mechanical compression of an interior cover, the nature of which is not specified, being produced by a traction handle and then a locking collar: the seal is provided by a circular pneumatic seal fastened to the periphery of the cover, which may be associated with capsules that can be split open or inflated by compressed air.
There may finally be cited various devices that attempt to plug the hole by an expansion of volume within that hole such as in the patent FR 2808499 (Acquaviva) which teaches an inflatable element that is inserted into the hole and that is inflated with compressed air or gas. The patent FR 2743347 (Montel) moreover describes a polymerizable substance reacting rapidly by expanding on contact with water which is therefore inserted into the hole to block it: a product of this kind is limited by its application method, which can only be manual, and to small holes, because it is necessary to hold the product for the time it takes to polymerize and to expand while attempting to maintain the pressure of the water and the seal, which is not easy to do at the same time.
Although, like the present invention, all these products or devices have the objective of blocking or sealing a hole causing, in the case of a boat, a leak in a wall, they all have at least one of the following disadvantages:
their use is complicated and/or limited by the force caused by the pressure of the water as soon as the hole is more than a few centimeters in diameter,
it is not really possible to block or seal irregular breaches with most of these products,
the restrictive application to a plane surface, either on the outside of the hull, which is not always the case (breach in the stem, close to the keel or the rudder stock, the propshaft, etc.), or on the inside, which is never the case in modern pleasure boats,
the use of a rigid central shaft and threaded, sliding or articulated metal parts in contact: a system of this kind is difficult to use below the waterline of a ship in rough sea that is shipping water, and is liable to become jammed and to premature ageing when stored in a salty environment,
the necessary insertion of a more or less voluminous and fragile part of the system (umbrella, balloon, articulated anchor system) through the breach, impossible in practice because on the one hand of the high flow rate of water through even a small breach and on the other hand in the case of a narrow fissure,
blocking or sealing the hole from the outside of the hull possibly necessitating placement or at least checking by a diver, which is very restrictive in an emergency situation, and not easily compatible with continuing to sail the ship,
the necessary adaptation of the size and weight of the rigid parts of the system to the maximum area that it is required to block or seal, with the consequences thereof in respect of ease of use, overall size and weight in storage, and price.
The problem is therefore to answer these disadvantages and limitations of the existing systems, namely to block or seal, from inside a ship's hull, holes up to at least 20 dm2 (and therefore even larger), that are not only of circular shape but also of irregular shape (possibly being produced by an impact and/or a hull breach), with non-plane internal and external wall surfaces, with no complex mechanical parts nor insertion of a large and/or fragile part through the hole, and that is easy to use, of low cost and small overall size, and able to adapt to different sizes of holes to be blocked or sealed.